This is bird note.

Have you noticed those little brown birds with red breasts at your bird feeders?

Those are house finches, familiar birds all across North America.

The female housefinch is brown and streaked. The male, similar, but with bright red patches

on its head, breast, and rump. Researchers have shown that the red coloration of males is produced

from carotenoid pigments contained in the bird's diet. Carotenoids are the same pigments that give oranges and carrots their color,

the pigments that make goldfinches yellow and flamingos pink.

We also know that male house finches develop brighter plumage

when they're growing in new feathers if they eat more fruits containing carotenoids.

So, well-fed means bright red. When a male house

finch sings to attract a female, he's better off being well-fed because females prefer more

brightly colored males. Redder males also attract females in better condition, and such a pair raises, on the

average, more young. The message is clear. In the world of house finches, the way to romance

and a family begins with a good diet. For Bird Note, I'm Michael Stein.

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